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<FONT color="green">001</FONT>    /*<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT>     * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT>     * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT>     * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT>     * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT>     * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT>     *<a name="line.8"></a>
<FONT color="green">009</FONT>     *      http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT>     * See the License for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT>     * limitations under the License.<a name="line.15"></a>
<FONT color="green">016</FONT>     */<a name="line.16"></a>
<FONT color="green">017</FONT>    package org.apache.commons.math.genetics;<a name="line.17"></a>
<FONT color="green">018</FONT>    <a name="line.18"></a>
<FONT color="green">019</FONT>    import org.apache.commons.math.random.RandomGenerator;<a name="line.19"></a>
<FONT color="green">020</FONT>    import org.apache.commons.math.random.JDKRandomGenerator;<a name="line.20"></a>
<FONT color="green">021</FONT>    <a name="line.21"></a>
<FONT color="green">022</FONT>    /**<a name="line.22"></a>
<FONT color="green">023</FONT>     * Implementation of a genetic algorithm. All factors that govern the operation<a name="line.23"></a>
<FONT color="green">024</FONT>     * of the algorithm can be configured for a specific problem.<a name="line.24"></a>
<FONT color="green">025</FONT>     *<a name="line.25"></a>
<FONT color="green">026</FONT>     * @since 2.0<a name="line.26"></a>
<FONT color="green">027</FONT>     * @version $Revision: 925812 $ $Date: 2010-03-21 16:49:31 +0100 (dim. 21 mars 2010) $<a name="line.27"></a>
<FONT color="green">028</FONT>     */<a name="line.28"></a>
<FONT color="green">029</FONT>    public class GeneticAlgorithm {<a name="line.29"></a>
<FONT color="green">030</FONT>    <a name="line.30"></a>
<FONT color="green">031</FONT>        /**<a name="line.31"></a>
<FONT color="green">032</FONT>         * Static random number generator shared by GA implementation classes.<a name="line.32"></a>
<FONT color="green">033</FONT>         * Set the randomGenerator seed to get reproducible results.<a name="line.33"></a>
<FONT color="green">034</FONT>         * Use {@link #setRandomGenerator(RandomGenerator)} to supply an alternative<a name="line.34"></a>
<FONT color="green">035</FONT>         * to the default JDK-provided PRNG.<a name="line.35"></a>
<FONT color="green">036</FONT>         */<a name="line.36"></a>
<FONT color="green">037</FONT>        //@GuardedBy("this")<a name="line.37"></a>
<FONT color="green">038</FONT>        private static RandomGenerator randomGenerator = new JDKRandomGenerator();<a name="line.38"></a>
<FONT color="green">039</FONT>    <a name="line.39"></a>
<FONT color="green">040</FONT>        /** the crossover policy used by the algorithm. */<a name="line.40"></a>
<FONT color="green">041</FONT>        private final CrossoverPolicy crossoverPolicy;<a name="line.41"></a>
<FONT color="green">042</FONT>    <a name="line.42"></a>
<FONT color="green">043</FONT>        /** the rate of crossover for the algorithm. */<a name="line.43"></a>
<FONT color="green">044</FONT>        private final double crossoverRate;<a name="line.44"></a>
<FONT color="green">045</FONT>    <a name="line.45"></a>
<FONT color="green">046</FONT>        /** the mutation policy used by the algorithm. */<a name="line.46"></a>
<FONT color="green">047</FONT>        private final MutationPolicy mutationPolicy;<a name="line.47"></a>
<FONT color="green">048</FONT>    <a name="line.48"></a>
<FONT color="green">049</FONT>        /** the rate of mutation for the algorithm. */<a name="line.49"></a>
<FONT color="green">050</FONT>        private final double mutationRate;<a name="line.50"></a>
<FONT color="green">051</FONT>    <a name="line.51"></a>
<FONT color="green">052</FONT>        /** the selection policy used by the algorithm. */<a name="line.52"></a>
<FONT color="green">053</FONT>        private final SelectionPolicy selectionPolicy;<a name="line.53"></a>
<FONT color="green">054</FONT>    <a name="line.54"></a>
<FONT color="green">055</FONT>        /** the number of generations evolved to reach {@link StoppingCondition} in the last run. */<a name="line.55"></a>
<FONT color="green">056</FONT>        private int generationsEvolved = 0;<a name="line.56"></a>
<FONT color="green">057</FONT>    <a name="line.57"></a>
<FONT color="green">058</FONT>        /**<a name="line.58"></a>
<FONT color="green">059</FONT>         * @param crossoverPolicy The {@link CrossoverPolicy}<a name="line.59"></a>
<FONT color="green">060</FONT>         * @param crossoverRate The crossover rate as a percentage (0-1 inclusive)<a name="line.60"></a>
<FONT color="green">061</FONT>         * @param mutationPolicy The {@link MutationPolicy}<a name="line.61"></a>
<FONT color="green">062</FONT>         * @param mutationRate The mutation rate as a percentage (0-1 inclusive)<a name="line.62"></a>
<FONT color="green">063</FONT>         * @param selectionPolicy The {@link SelectionPolicy}<a name="line.63"></a>
<FONT color="green">064</FONT>         */<a name="line.64"></a>
<FONT color="green">065</FONT>        public GeneticAlgorithm(<a name="line.65"></a>
<FONT color="green">066</FONT>                CrossoverPolicy crossoverPolicy, double crossoverRate,<a name="line.66"></a>
<FONT color="green">067</FONT>                MutationPolicy mutationPolicy, double mutationRate,<a name="line.67"></a>
<FONT color="green">068</FONT>                SelectionPolicy selectionPolicy) {<a name="line.68"></a>
<FONT color="green">069</FONT>            if (crossoverRate &lt; 0 || crossoverRate &gt; 1) {<a name="line.69"></a>
<FONT color="green">070</FONT>                throw new IllegalArgumentException("crossoverRate must be between 0 and 1");<a name="line.70"></a>
<FONT color="green">071</FONT>            }<a name="line.71"></a>
<FONT color="green">072</FONT>            if (mutationRate &lt; 0 || mutationRate &gt; 1) {<a name="line.72"></a>
<FONT color="green">073</FONT>                throw new IllegalArgumentException("mutationRate must be between 0 and 1");<a name="line.73"></a>
<FONT color="green">074</FONT>            }<a name="line.74"></a>
<FONT color="green">075</FONT>            this.crossoverPolicy = crossoverPolicy;<a name="line.75"></a>
<FONT color="green">076</FONT>            this.crossoverRate = crossoverRate;<a name="line.76"></a>
<FONT color="green">077</FONT>            this.mutationPolicy = mutationPolicy;<a name="line.77"></a>
<FONT color="green">078</FONT>            this.mutationRate = mutationRate;<a name="line.78"></a>
<FONT color="green">079</FONT>            this.selectionPolicy = selectionPolicy;<a name="line.79"></a>
<FONT color="green">080</FONT>        }<a name="line.80"></a>
<FONT color="green">081</FONT>    <a name="line.81"></a>
<FONT color="green">082</FONT>        /**<a name="line.82"></a>
<FONT color="green">083</FONT>         * Set the (static) random generator.<a name="line.83"></a>
<FONT color="green">084</FONT>         *<a name="line.84"></a>
<FONT color="green">085</FONT>         * @param random random generator<a name="line.85"></a>
<FONT color="green">086</FONT>         */<a name="line.86"></a>
<FONT color="green">087</FONT>        public static synchronized void setRandomGenerator(RandomGenerator random) {<a name="line.87"></a>
<FONT color="green">088</FONT>            randomGenerator = random;<a name="line.88"></a>
<FONT color="green">089</FONT>        }<a name="line.89"></a>
<FONT color="green">090</FONT>    <a name="line.90"></a>
<FONT color="green">091</FONT>        /**<a name="line.91"></a>
<FONT color="green">092</FONT>         * Returns the (static) random generator.<a name="line.92"></a>
<FONT color="green">093</FONT>         *<a name="line.93"></a>
<FONT color="green">094</FONT>         * @return the static random generator shared by GA implementation classes<a name="line.94"></a>
<FONT color="green">095</FONT>         */<a name="line.95"></a>
<FONT color="green">096</FONT>        public static synchronized RandomGenerator getRandomGenerator() {<a name="line.96"></a>
<FONT color="green">097</FONT>            return randomGenerator;<a name="line.97"></a>
<FONT color="green">098</FONT>        }<a name="line.98"></a>
<FONT color="green">099</FONT>    <a name="line.99"></a>
<FONT color="green">100</FONT>        /**<a name="line.100"></a>
<FONT color="green">101</FONT>         * Evolve the given population. Evolution stops when the stopping condition<a name="line.101"></a>
<FONT color="green">102</FONT>         * is satisfied. Updates the {@link #getGenerationsEvolved() generationsEvolved}<a name="line.102"></a>
<FONT color="green">103</FONT>         * property with the number of generations evolved before the StoppingCondition<a name="line.103"></a>
<FONT color="green">104</FONT>         * is satisfied.<a name="line.104"></a>
<FONT color="green">105</FONT>         *<a name="line.105"></a>
<FONT color="green">106</FONT>         * @param initial the initial, seed population.<a name="line.106"></a>
<FONT color="green">107</FONT>         * @param condition the stopping condition used to stop evolution.<a name="line.107"></a>
<FONT color="green">108</FONT>         * @return the population that satisfies the stopping condition.<a name="line.108"></a>
<FONT color="green">109</FONT>         */<a name="line.109"></a>
<FONT color="green">110</FONT>        public Population evolve(Population initial, StoppingCondition condition) {<a name="line.110"></a>
<FONT color="green">111</FONT>            Population current = initial;<a name="line.111"></a>
<FONT color="green">112</FONT>            generationsEvolved = 0;<a name="line.112"></a>
<FONT color="green">113</FONT>            while (!condition.isSatisfied(current)) {<a name="line.113"></a>
<FONT color="green">114</FONT>                current = nextGeneration(current);<a name="line.114"></a>
<FONT color="green">115</FONT>                generationsEvolved++;<a name="line.115"></a>
<FONT color="green">116</FONT>            }<a name="line.116"></a>
<FONT color="green">117</FONT>            return current;<a name="line.117"></a>
<FONT color="green">118</FONT>        }<a name="line.118"></a>
<FONT color="green">119</FONT>    <a name="line.119"></a>
<FONT color="green">120</FONT>        /**<a name="line.120"></a>
<FONT color="green">121</FONT>         * &lt;p&gt;Evolve the given population into the next generation.&lt;/p&gt;<a name="line.121"></a>
<FONT color="green">122</FONT>         * &lt;p&gt;&lt;ol&gt;<a name="line.122"></a>
<FONT color="green">123</FONT>         *    &lt;li&gt;Get nextGeneration population to fill from &lt;code&gt;current&lt;/code&gt;<a name="line.123"></a>
<FONT color="green">124</FONT>         *        generation, using its nextGeneration method&lt;/li&gt;<a name="line.124"></a>
<FONT color="green">125</FONT>         *    &lt;li&gt;Loop until new generation is filled:&lt;/li&gt;<a name="line.125"></a>
<FONT color="green">126</FONT>         *    &lt;ul&gt;&lt;li&gt;Apply configured SelectionPolicy to select a pair of parents<a name="line.126"></a>
<FONT color="green">127</FONT>         *            from &lt;code&gt;current&lt;/code&gt;&lt;/li&gt;<a name="line.127"></a>
<FONT color="green">128</FONT>         *        &lt;li&gt;With probability = {@link #getCrossoverRate()}, apply<a name="line.128"></a>
<FONT color="green">129</FONT>         *            configured {@link CrossoverPolicy} to parents&lt;/li&gt;<a name="line.129"></a>
<FONT color="green">130</FONT>         *        &lt;li&gt;With probability = {@link #getMutationRate()}, apply<a name="line.130"></a>
<FONT color="green">131</FONT>         *            configured {@link MutationPolicy} to each of the offspring&lt;/li&gt;<a name="line.131"></a>
<FONT color="green">132</FONT>         *        &lt;li&gt;Add offspring individually to nextGeneration,<a name="line.132"></a>
<FONT color="green">133</FONT>         *            space permitting&lt;/li&gt;<a name="line.133"></a>
<FONT color="green">134</FONT>         *    &lt;/ul&gt;<a name="line.134"></a>
<FONT color="green">135</FONT>         *    &lt;li&gt;Return nextGeneration&lt;/li&gt;<a name="line.135"></a>
<FONT color="green">136</FONT>         *    &lt;/ol&gt;<a name="line.136"></a>
<FONT color="green">137</FONT>         * &lt;/p&gt;<a name="line.137"></a>
<FONT color="green">138</FONT>         *<a name="line.138"></a>
<FONT color="green">139</FONT>         * @param current the current population.<a name="line.139"></a>
<FONT color="green">140</FONT>         * @return the population for the next generation.<a name="line.140"></a>
<FONT color="green">141</FONT>         */<a name="line.141"></a>
<FONT color="green">142</FONT>        public Population nextGeneration(Population current) {<a name="line.142"></a>
<FONT color="green">143</FONT>            Population nextGeneration = current.nextGeneration();<a name="line.143"></a>
<FONT color="green">144</FONT>    <a name="line.144"></a>
<FONT color="green">145</FONT>            RandomGenerator randGen = getRandomGenerator();<a name="line.145"></a>
<FONT color="green">146</FONT>    <a name="line.146"></a>
<FONT color="green">147</FONT>            while (nextGeneration.getPopulationSize() &lt; nextGeneration.getPopulationLimit()) {<a name="line.147"></a>
<FONT color="green">148</FONT>                // select parent chromosomes<a name="line.148"></a>
<FONT color="green">149</FONT>                ChromosomePair pair = getSelectionPolicy().select(current);<a name="line.149"></a>
<FONT color="green">150</FONT>    <a name="line.150"></a>
<FONT color="green">151</FONT>                // crossover?<a name="line.151"></a>
<FONT color="green">152</FONT>                if (randGen.nextDouble() &lt; getCrossoverRate()) {<a name="line.152"></a>
<FONT color="green">153</FONT>                    // apply crossover policy to create two offspring<a name="line.153"></a>
<FONT color="green">154</FONT>                    pair = getCrossoverPolicy().crossover(pair.getFirst(), pair.getSecond());<a name="line.154"></a>
<FONT color="green">155</FONT>                }<a name="line.155"></a>
<FONT color="green">156</FONT>    <a name="line.156"></a>
<FONT color="green">157</FONT>                // mutation?<a name="line.157"></a>
<FONT color="green">158</FONT>                if (randGen.nextDouble() &lt; getMutationRate()) {<a name="line.158"></a>
<FONT color="green">159</FONT>                    // apply mutation policy to the chromosomes<a name="line.159"></a>
<FONT color="green">160</FONT>                    pair = new ChromosomePair(<a name="line.160"></a>
<FONT color="green">161</FONT>                        getMutationPolicy().mutate(pair.getFirst()),<a name="line.161"></a>
<FONT color="green">162</FONT>                        getMutationPolicy().mutate(pair.getSecond()));<a name="line.162"></a>
<FONT color="green">163</FONT>                }<a name="line.163"></a>
<FONT color="green">164</FONT>    <a name="line.164"></a>
<FONT color="green">165</FONT>                // add the first chromosome to the population<a name="line.165"></a>
<FONT color="green">166</FONT>                nextGeneration.addChromosome(pair.getFirst());<a name="line.166"></a>
<FONT color="green">167</FONT>                // is there still a place for the second chromosome?<a name="line.167"></a>
<FONT color="green">168</FONT>                if (nextGeneration.getPopulationSize() &lt; nextGeneration.getPopulationLimit()) {<a name="line.168"></a>
<FONT color="green">169</FONT>                    // add the second chromosome to the population<a name="line.169"></a>
<FONT color="green">170</FONT>                    nextGeneration.addChromosome(pair.getSecond());<a name="line.170"></a>
<FONT color="green">171</FONT>                }<a name="line.171"></a>
<FONT color="green">172</FONT>            }<a name="line.172"></a>
<FONT color="green">173</FONT>    <a name="line.173"></a>
<FONT color="green">174</FONT>            return nextGeneration;<a name="line.174"></a>
<FONT color="green">175</FONT>        }<a name="line.175"></a>
<FONT color="green">176</FONT>    <a name="line.176"></a>
<FONT color="green">177</FONT>        /**<a name="line.177"></a>
<FONT color="green">178</FONT>         * Returns the crossover policy.<a name="line.178"></a>
<FONT color="green">179</FONT>         * @return crossover policy<a name="line.179"></a>
<FONT color="green">180</FONT>         */<a name="line.180"></a>
<FONT color="green">181</FONT>        public CrossoverPolicy getCrossoverPolicy() {<a name="line.181"></a>
<FONT color="green">182</FONT>            return crossoverPolicy;<a name="line.182"></a>
<FONT color="green">183</FONT>        }<a name="line.183"></a>
<FONT color="green">184</FONT>    <a name="line.184"></a>
<FONT color="green">185</FONT>        /**<a name="line.185"></a>
<FONT color="green">186</FONT>         * Returns the crossover rate.<a name="line.186"></a>
<FONT color="green">187</FONT>         * @return crossover rate<a name="line.187"></a>
<FONT color="green">188</FONT>         */<a name="line.188"></a>
<FONT color="green">189</FONT>        public double getCrossoverRate() {<a name="line.189"></a>
<FONT color="green">190</FONT>            return crossoverRate;<a name="line.190"></a>
<FONT color="green">191</FONT>        }<a name="line.191"></a>
<FONT color="green">192</FONT>    <a name="line.192"></a>
<FONT color="green">193</FONT>        /**<a name="line.193"></a>
<FONT color="green">194</FONT>         * Returns the mutation policy.<a name="line.194"></a>
<FONT color="green">195</FONT>         * @return mutation policy<a name="line.195"></a>
<FONT color="green">196</FONT>         */<a name="line.196"></a>
<FONT color="green">197</FONT>        public MutationPolicy getMutationPolicy() {<a name="line.197"></a>
<FONT color="green">198</FONT>            return mutationPolicy;<a name="line.198"></a>
<FONT color="green">199</FONT>        }<a name="line.199"></a>
<FONT color="green">200</FONT>    <a name="line.200"></a>
<FONT color="green">201</FONT>        /**<a name="line.201"></a>
<FONT color="green">202</FONT>         * Returns the mutation rate.<a name="line.202"></a>
<FONT color="green">203</FONT>         * @return mutation rate<a name="line.203"></a>
<FONT color="green">204</FONT>         */<a name="line.204"></a>
<FONT color="green">205</FONT>        public double getMutationRate() {<a name="line.205"></a>
<FONT color="green">206</FONT>            return mutationRate;<a name="line.206"></a>
<FONT color="green">207</FONT>        }<a name="line.207"></a>
<FONT color="green">208</FONT>    <a name="line.208"></a>
<FONT color="green">209</FONT>        /**<a name="line.209"></a>
<FONT color="green">210</FONT>         * Returns the selection policy.<a name="line.210"></a>
<FONT color="green">211</FONT>         * @return selection policy<a name="line.211"></a>
<FONT color="green">212</FONT>         */<a name="line.212"></a>
<FONT color="green">213</FONT>        public SelectionPolicy getSelectionPolicy() {<a name="line.213"></a>
<FONT color="green">214</FONT>            return selectionPolicy;<a name="line.214"></a>
<FONT color="green">215</FONT>        }<a name="line.215"></a>
<FONT color="green">216</FONT>    <a name="line.216"></a>
<FONT color="green">217</FONT>        /**<a name="line.217"></a>
<FONT color="green">218</FONT>         * Returns the number of generations evolved to<a name="line.218"></a>
<FONT color="green">219</FONT>         * reach {@link StoppingCondition} in the last run.<a name="line.219"></a>
<FONT color="green">220</FONT>         *<a name="line.220"></a>
<FONT color="green">221</FONT>         * @return number of generations evolved<a name="line.221"></a>
<FONT color="green">222</FONT>         * @since 2.1<a name="line.222"></a>
<FONT color="green">223</FONT>         */<a name="line.223"></a>
<FONT color="green">224</FONT>        public int getGenerationsEvolved() {<a name="line.224"></a>
<FONT color="green">225</FONT>            return generationsEvolved;<a name="line.225"></a>
<FONT color="green">226</FONT>        }<a name="line.226"></a>
<FONT color="green">227</FONT>    <a name="line.227"></a>
<FONT color="green">228</FONT>    }<a name="line.228"></a>




























































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